user
In a short paragraph, explain how a blockchain works.

Answer:
assistant
A blockchain is a distributed ledger technology that enables the recording, tracing and approval of digital data in a secure, decentralized manner. It is made up of individual blocks, each containing a cryptographic hash of the previous block, a timestamp and transaction data. This data is then distributed among multiple computers on the network, making it impossible to manipulate or tamper with. Every time a new transaction takes place, it is validated by the network and once approved, it is added to the chain with an updated timestamp and the new block. This ensures a complete and secure record of all activity that takes place on the blockchain.